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Finding the Fourth Proportional to 28.72, 39.68 and 20.53

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Solution

The fourth proportional to 28.72, 39.68 and 20.53 is: 28.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.72 : 39.68 = 20.53 : x
  2. Step 2: Convert to fraction form
    28.72/39.68 = 20.53/x
  3. Step 3: Cross multiply
    28.72x = 39.68 × 20.53
  4. Step 4: Simplify right side
    28.72x = 814.63
  5. Step 5: Solve for x
    x = 814.63/28.72
  6. Step 6: Final answer
    x = 28.36

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.